This invention relates to an apparatus for controlling and reducing the adhesive force of an adhesive agent for the purpose of simplifying and easing the removal of a semiconductor wafer such as a silicon wafer or the like adhered to a substrate such as a synthetic resin film or the like from the substrate.
A process has been known wherein, after a semiconductor wafer is applied with a circuit forming treatment, such as by etching or the like so that IC circuits are formed thereon, the wafer is adhered by an adhesive agent to a substrate such as a synthetic resin film or the like to form a workpiece. The wafer is then cut into IC dice. Thereafter each bare die is taken off of the substrate and mounted in a package to form an IC chip. In this case, it is desireable that each bare die taken off of the substrate be free of any contamination, such as any part of the adhesive agent transferred to a rear surface of the die. As disclosed in Japanese Patent Application Publication Sho No. 58-50164, a photo-setting type adhesive agent has been proposed to be used. The photo-setting adhesive agent is hardened or cured by irradiation. That is, after cutting the wafer into dice, the photo-setting adhesive agent is irradiated by shining a light thereonto. This results in a decrease in the adhesive strength of the agent. In this manner, transfer of the adhesive agent to the rear surface of each die can be prevented when the die is taken off of the substrate.
Additionally, a process has been known wherein a cassette casing is prepared containing plurality of the workpieces. Each workpiece is taken out, one by one, from the casing and subjected to the foregoing photo-setting treatment of the adhesive agent thereof. Thereafter the individual treated workpiece is conveyed into an empty cassette casing for being conveyed to the next treating step.
In this case, the amount of time of irradiation of light thereon required for sufficiently decreasing an adhesive force or strength of the photo-setting adhesive agent of the workpiece is above 10 seconds, even in a case where the adhesive agent has a quick hardening property. Such a period of time is too long as a photo-setting treatment time for an IC chip manufacturing process and is not desirable.